Back strap for a sandal



FIG. 1 is a side elevational view of one side of the back strap for a sandal showing our new design;

FIG. 2 is a side elevational view of the other side of the back strap shown in FIG. 1;

FIG. 3 is a top plan view of the back strap shown in FIG. 1;

FIG. 4 is a front elevational view of the back strap shown in FIG. 1; and,

FIG. 5 is a rear elevational view of the back strap shown in FIG. 1.

The broken line showing of a sole periphery and the remaining parts of the sandal in FIGS. 1-5 are for illustrative purposes and from no part of the claimed design. 

The ornamental design for a back strap for a sandal, as shown and described. 